BIOL 253 EXAM 1 QUESTIONS & ANSWERS(RATED A+)

BIOL 253 EXAM 1 QUESTIONS &
ANSWERS(RATED A+)
Which of the following transport mechanisms may be utilized to move glucose across
cell membranes? - ANSWERSecondary active transport and facilitated diffusion

Which of the following statements about the Na-K pump is(are) true? - ANSWERThe
location of the binding sites on the Na-K pump dictates the direction of solute
movement.

Examples of active transport may include __________. - ANSWERthe movement of
Na+ ions out of cells and the movement of glucose molecules into intestinal epithelial
cells

Which of the following statements about epithelial transport in the intestines is (are)
true? - ANSWERThe Na+/K+ ATPase is found only in the basolateral membrane of
intestinal epithelial cells and the movement of Na+ ions across the apical membrane
of intestinal epithelial cells is dependent on the electrochemical gradient created by
the Na+/K+ ATPase.

Which of the following statements is false with regard to primary/secondary active
transport? - ANSWERSubstances will always move down their concentration
gradient.

If a cell were to become depleted of its ATP, which type of membrane transport
would be most directly and immediately affected? - ANSWERPrimary active
transport

Energy released by the hydrolysis of ATP is used to move K+ and Na+ across cell
membranes. This process is called __________. - ANSWERprimary active transport

Which of the following will always be true of primary and secondary active transport?
- ANSWERAt least one substance will move against its concentration gradient.

Which of the following statements makes an accurate comparison between primary
and secondary active transport? - ANSWERIn primary active transport ATP is
directly utilized, while in secondary active transport the potential energy of a
concentration gradient is utilized.

Transport processes that require an energy source include __________. -
ANSWERprimary active transport and secondary active transport


Substances that are going to move against their concentration gradient (from low
concentration to high concentration) will use which type(s) of membrane transport? -
ANSWERPrimary or secondary active transport

, In skeletal muscle, the sarcoplasmic reticulum stores a very high concentration of
Ca++. When Ca++ is released into the cytosol of muscle to facilitate contraction, it
needs to be removed and pumped back into the sarcoplasmic reticulum so that
skeletal muscle can return to its relaxed state. The Ca++ is moved from cytosol and
pumped back into the sarcoplasmic reticulum where its concentration is much
higher. What type of membrane transport does this represent? - ANSWERPrimary
active transport

What is similar between facilitated diffusion and primary/secondary active transport?
In both forms of transport __________. - ANSWERa membrane transport protein is
involved

Identify which of the following is the correct definition of primary active transport. -
ANSWERIt is mediated by a protein that directly uses ATP energy to move a
substance against its concentration gradient.

If many solutes are constantly being pumped into or out of cells, why don't the
intracellular concentrations of these solutes change? - ANSWERFor any given
solute, the rate of active transport in one direction is equal to the passive movement
(leak) of the solute in the opposite direction.

Transport processes that can be saturated include __________. - ANSWERPrimary
active transport, Secondary active transport, Facilitated diffusion, ion channel
proteins
Which of the following molecules would not simply diffuse through cell membranes
easily? - ANSWERNa+ ions and glucose

As the solute concentration of a solution increases, __________. - ANSWERthe
water concentration decreases and the osmotic pressure increases

Which of the following types of molecules would be most likely to pass through the
plasma membrane by means of simple diffusion? - ANSWEROxygen - nonpolar

In order for water to be absorbed by epithelial cells, __________. -
ANSWERaquaporins must be present in the cell membranes and the concentration
of impermeable solutes must be higher on the inside of the cell

Which of the following does not require the use of ATP? - ANSWEROsmosis

In comparing a solution to a fluid in a cell, a hypertonic solution always has
__________. - ANSWERa higher concentration of non-penetrating solutes than that
in the cell

Facilitated diffusion differs from simple diffusion in what way(s)? - ANSWERThe rate
of facilitated diffusion depends on the number of carriers in the membrane.

The rate of diffusion, or flux, of particles across a membrane is dependent on
__________. - ANSWERAll of the listed responses are correct.